"If life really does form readily in Earth-like conditions, it should have started many times right here on Earth, so we should look for a 'shadow biosphere' of life, but not as we know it, under our very noses.'"

Although there is plenty of habitable real estate out there, "habitable" is not the same as "inhabited," says Arizona State University Regents Professor and noted cosmologist Paul Davies. Because nobody knows how non-life transitioned to life on Earth, it is impossible to estimate the odds of it springing forth elsewhere in the universe.

In its most advanced forms, Davies has aruged, life may exists in forms beyond matter as we know it. That it might have no fixed size or shape; have no well-defined boundaries. Is dynamical on all scales of space and time. Or, conversely, does not appear to do anything at all that we can discern. Does not consist of discrete, separate things; but rather it is a system, or a subtle higher-level correlation of things.

Are matter and information, Davies asks, all there is? Five hundred years ago, Davies writes, " the very concept of a device manipulating information, or software, would have been incomprehensible. Might there be a still higher level, as yet outside all human experience, that organizes electrons?

If so, this "third level" would never be manifest through observations made at the informational level, still less at the matter level.

We should be open to the distinct possibility that advanced alien technology a billion years old may operate at the third, or perhaps even a fourth or fifth level -all of which are totally incomprehensible to the human mind at our current state of evolution in 2018.

Davies presented his findings during a press briefing Feb. 16 at the annual meeting of the American Association for the Advancement of Science in Austin, Texas.

"During my career, opinion has shifted from life's origin being a bizarre fluke unique in the universe ('almost a miracle' in the words of Francis Crick), to the belief that the universe is teeming with life ('a cosmic imperative' in the words of Christian de Duve)," Davies said. "How can we settle the matter? For several decades astronomers have been sweeping the skies with radio telescopes hoping to stumble across a message from ET. So far they have been met by an 'eerie silence.'"

Davies is a cosmologist, theoretical physicist, astrobiologist and best-selling author. His latest book 'The Eerie Silence" is a celebration and critique of the search for cosmic company.

Davies is a member of the Breakthrough Listen Committee and formerly chaired the SETI Post-Detection Task group of the International Academy of Astronautics. He was the first person to champion the idea that life on Earth may have originated on Mars and transferred here in impact ejecta. Davies is director of the Beyond Center at ASU that researches how life began in terms of the organization of information in complex networks – the software of life. His forthcoming book "The Demon in the Machine," is a penetrating look at the power of information to explain the physics of living matter.